1. Field of the Invention
The present invention relates to a triggered service. More particularly, the present invention relates to a mobility triggered service in which a position of a target set is calculated when the target set moves.
2. Description of the Related Art
In general, a triggered service refers to a service in which calculation of a position value of a target set is periodically or aperiodically repeated with conditions previously established (i.e., a periodic triggered service), or in which if the target set reaches or gets out of a predetermined area, an event is considered to be happening (i.e., area triggered service), the position value of the target set is calculated, and then the calculated position value is provided to a Secure User Plane Location (SUPL) agent.
Among the above conventional methods for providing services in which position information is repeatedly provided with conditions previously established, the periodic triggered service will be described with reference to FIG. 1.
A. A SUPL agent 101 periodically sends a Mobile Location Protocol Triggered Location Request Report (MLP TLRR) to a Home SUPL Location Platform (H-SLP) 103. Then, H-SLP 103 verifies periodic location service authority of the SUPL agent 101 by using CLIENT IDentification (ID) corresponding to a unique identifier of the SUPL agent 101. If the location service authority of the SUPL agent 101 is valid, the SUPL agent 101 verifies if the SUPL agent 101 can use the position value of a target set 105 by using Mobile Station IDentification (MSID) corresponding to an identifier of the target set 105 which has made a request. A method used at this time is to make a decision by verifying a subscriber privacy profile of the target set 105 that a terminal user of the target set 105 has already defined. The subscriber privacy file corresponds to a list which is prepared by the terminal user of the target set 105, and which includes persons who can use the position value of the terminal user. At this point, identifiers representing the persons who can use the position value of the terminal user of the target set 105 are produced by using the respective IDs of the target sets used by the persons. The identifiers used at this moment may be, e.g., a Mobile Station International Integrated System Digital Network (ISDN) Number (MSISDN), including a telephone number and the like.
B. The H-SLP 103 verifies if the target set 105 is in a process of roaming, and also verifies if the target set 105 can use SUPL protocol employed in calculating a position. This is why it is assumed that the position of the target set 105 is calculated by using the SUPL protocol in an exemplary embodiment of the present invention. However, it is needless to say that this is nothing but an exemplary embodiment of the present invention, and an exemplary embodiment of the present invention may also be applied to a case where another position calculation protocol is employed. Thus, it goes without saying that the H-SLP 103 is allowed to verify if the target set 105 uses a relevant position calculation protocol in the case where another position calculation protocol is employed, the H-SLP 103.
C. The H-SLP 103 sends a SUPL INITiate (INIT) message required to initiate a position calculation to the target set 105, and starts a periodic location service. Then, a method for transmitting the SUPL INIT message may be implemented by using a Wireless Application Protocol (WAP) push method or a Short Message Service (SMS) trigger method. The SUPL INIT message includes a SESSION ID which represents a session currently linked between the H-SLP 103 and the target set 105, a TRIGGER-TYPE which represents kinds of periodic location services, a POSMETHOD which represents a position calculation method, and a SLP MODE which represents the form of the H-SLP 103.
D. Upon receiving the SUPL INIT message, the target set 105 is linked to the H-SLP 103 via a data network.
E. The target set 105 sends a SUPL TRIGGERED START message required to start a location service. Then, the SUPL TRIGGERED START message includes parameters, such as a SESSION ID, a Location ID (LID) which represents information of a network in which the target set 105 exists at present, a SET-CAPABILITIES which represents a position calculation method and the like.
F. The H-SLP determines a position calculation method (i.e., a positioning method) by transmitting a SUPL TRIGGERED RESPONSE message, and transmits conditions of the periodic location service to the target set 105.
G. The H-SLP 103 transmits a Mobile Location Protocol Triggered Location Request Answer (MLP TLRA) message to the SUPL agent 101, and gives notice that the requested periodic location service is started.
H. The target set 105 memorizes a period in order to perform a position calculation, and transmits a SUPL POS INIT message required to initiate a position calculation at the expiration of a relevant period. At this time, the target set 105 transmits a SESSION ID and a Location ID (LID) which represents information of a network in which the target set 105 itself exists at present.
I. The H-SLP 103 and the target set 105 perform the position calculation.
J. The H-SLP 103 transmits the calculated position value to the SUPL agent 101.
Among the above steps, H, I and J steps occur repeatedly while the periodic location service is provided.
K, L, and M steps are substantially the same as H, I and J steps, respectively.
Therefore, the target set sends, to the H-SLP, a message required to initiate a position calculation process occurring during the periodic location service in the conventional periodic triggered service. Namely, the target set memorizes a period so as to perform the position calculation by periods, and if the period begins, the target set regards it as the occurrence of an event. At this time, the target set transmits, to the H-SLP, a message requesting the position calculation process to be initiated. Then, the H-SLP receives, from the target set, the message requesting the position calculation (i.e., a positioning session) process to be initiated, and from that time, initiates the position calculation process.
Namely, only the target set determines the period at which the position calculation is performed, and the H-SLP only detects, from the target set, the message requesting the position calculation process to be initiated. Accordingly, the H-SLP waits for only the reception of the message requesting the position calculation process to be initiated, and only after the message has been received, the process for calculating a position of the target set is started.
Therefore, the prior art has such drawbacks that if the target set misses determining the period at which the position of the target set is calculated, the target set does not transmit, to the H-SLP, the message requesting the position calculation process to be initiated, and accordingly the position calculation process does not occur. After all, since the position value is not calculated at a relevant period, the service for providing the position of the target set is not implemented.
Also, even though there exists the area triggered service in which the position value of the target set is calculated if the target set arrives at a prescribed area with the prescribed area previously established, at present, the real state of things shows that there exists no services in which with a change of a position of a target set itself regarded as an event, the position value is calculated, and then a SUPL agent is informed of the calculated position value.